Copper is an excellent electrical conductor. Most of its uses are based on this property or the fact that it is also a good thermal conductor. However, many of its applications also rely on one or more of its other properties. For example, it wouldn't make very good water and gas pipes if it were highly reactive. On this page, we look at these other properties:

Picture 9. Brass can be polished up to give an attractive gold finish.

Easily joined

Copper can be joined easily by soldering or brazing. This is useful for pipework and for making sealed copper vessels.

Ductile

Copper is a ductile metal. This means that it can easily be shaped into pipes and drawn into wires.

Copper pipes are lightweight because they can have thin walls. They don't corrode and they can be bent to fit around corners. The pipes can be joined by soldering and they are safe in fires because they don't burn or support combustion.

Tough

Copper and copper alloys are tough. This means that they were well suited to being used for tools and weapons. Imagine the joy of ancient man when he discovered that his carefully formed arrowheads no longer shattered on impact.

The property of toughness is vital for copper and copper alloys in the modern world. They do not shatter when they are dropped or become brittle when cooled below 0°C.

Non magnetic

Copper is non magnetic and non sparking. Because of this, it is used in special tools and military applications.

Attractive colour

Copper and its alloys, such as brass, are used for jewellery and ornaments. They have an attractive golden colour which varies with the copper content. They have a good resistance to tarnishing making them last a long a time.

Picture 10. Roll over the properties above to see which metals give copper alloys those properties.

Alloys easily

Copper can be combined with other metals to make alloys. The most well known are brass and bronze. Although copper has excellent electrical and thermal properties, it needs to be hardened and strengthened for many industrial applications. It is therefore mixed with other metals and melted. The liquid metals form a solution which, when they solidify, are called alloys. Some copper alloys are:

brass: copper + zinc

bronze: copper + tin

cupro nickel: copper + nickel

The alloys are harder, stronger and tougher than pure copper. They can be made even harder by hammering them - a process called work hardening.

In ancient times, the first alloys could be made in the temperatures of a camp fire. This led to the Bronze Age.

Copper can be recycled without any loss of quality. 40% of the world's demand is met by recycled copper (see extracting copper).

Catalytic compounds

Copper can act as a catalyst. For example, it speeds up the reaction between zinc and dilute sulphuric acid. It is found in some enzymes, one of which is involved in respiration. So it really is a vital element.

Question 5

The table shows some uses of copper. In each case, the use relies on particular properties. Click on the buttons to show which properties each use should have.